Families with Latino backgrounds now represent the largest ethnic minority group in the United States, and adolescents wtihin the$8 families face substantial challenges to their psychological and behavioral adjustment. Emerging evidence indicates that traditional family values and practices may play a critical role in shaping Latino adolescents'risk for a number of problematic outcomes, including externalizing behavior problems, substance use, symptoms of depression and anxiety, and school disengagement and dropout. Family obligation and assistance have been identified as key elements of famHy relationships among famUies with Mexican baCkgrounds, the single largest LaUno ethnic group. Family obligation and assistance also have been shown to be Significant predictOf"S of adolescents'adjustment, induding their involvement in substarx:e use and theil" psychological well being. But ills stlD unclear 'Nhich facets of family obligation and assistance are sources of strength and which are challenges for the adolescents'adjustment. Withoutltlis information, it Is difficult to develop meaningful programs and policies that focus on this growing population of adolescents. The proposed research study fills th is gap in prior research by taking an approach that family membership functions as a social identity for adolescents from Mexican backgrounds, and uses several prInciples of Social Identity Tl1eory in order to address four kay questions: (1) How ara family obligation and assistance socialized within families from Mexican backgrounds?: (2) How does actuallamily assistan~ depend upon the families'daily needs and routines?;(3) How does lamily obligation and assistance impact adolescents'emotional and behavioral adjustment?;and (4) How do the dynamics of family obligation and assistance vary aCCOl"ding 10 characteristics of the adolescents'themselves? The proposed stud~'will address these key questions employing mixed methods, including traditional quantitative interviews, daily diary checktists, and qualitative IntervieWS. The study will take place in the Los Angeles metropolitan area, a primary location of families wilh Mexican backgrounds in the United Slates. A total of 540 adolescents wi! be recruited from the ninth and tenth grades of three high schools. Adolescents and their parents will comptete a personal interview and a fourteen day diary checklist for two consecutive years. In addition, a subset Of 54 families will annually participate in the Ecocultural Family Interview, which is an established qualitative Interview designed to provide a more In-depth view of the dynamics of the socialization, daily manifestation, and developmental implications of family obligation and assistance.